ABSTRACT

Our current knowledge of the vocal behaviour of Palaeognathae is limited, although it may increase our understanding of the evolution of avian vocal behaviour. The Greater Rhea (Rhea americana) has a complex syrinx, and males produce guttural sounds during the courtship display, which makes this species an interesting model to study vocal behaviour in ratites. We recorded a group of Greater Rheas living in semi-captive conditions at the zoo of the UFMT for eight days. A total of 749 booming calls were detected. The vocal activity of the Greater Rhea was maximum during the first four hours after sunrise, with a second peak before sunset. The species showed nocturnal vocal activity, as also found in a recent study on a diurnal tinamou. The number of vocalising birds during the recording period was unknown, and our data were collected during a restricted time window. Our results suggest that acoustic communication and nocturnal activity of the species might be more relevant than previously described. Passive acoustic monitoring may have further implications for the continued study of vocal activity in ratites. Further research should examine whether the vocal behaviour and nocturnal vocal activity of the Greater Rhea are also important in wild individuals.

摘要

我们目前对古颌动物发声行为的了解是有限的，尽管它可能会增加我们对鸟类发声行为进化的理解。大雷亚 ( Rhea americana)) 有一个复杂的 syrinx，雄性在求偶展示期间会发出喉音，这使得这个物种成为研究平胸动物发声行为的有趣模型。我们记录了一群在 UFMT 动物园半圈养条件下生活了八天的大雷亚斯。共检测到 749 个蓬勃发展的呼叫。大瑞亚的发声活动在日出后的前四个小时达到最大，在日落前出现第二个高峰。该物种表现出夜间发声活动，最近对昼夜活动的研究也发现了这一点。记录期间发声的鸟类数量未知，我们的数据是在有限的时间窗口内收集的。我们的结果表明，该物种的声学交流和夜间活动可能比之前描述的更相关。被动声学监测可能对继续研究平胸动物的声音活动有进一步的意义。进一步的研究应该检查大瑞亚的发声行为和夜间发声活动是否对野生个体也很重要。